Coin operated systems such as pay telephones typically include coin escrow devices which temporarily hold deposited coins until a determination is made as to whether the coins should be returned to the system user or collected in the systems coin box. A pay telephone, for example, releases coins to a coin box in the event that a call has been successfully placed or returns coins to the calling party in the event that a call is not successfully connected to a called party.
A primary requirement for a coin escrow device is reliability. A commercial coin escrow device must properly operate to discharge all escrowed coins to a coin box only when a transaction has been successfully completed and, conversely, must return all escrowed coins to the system user when a transaction has not been successfully completed or canceled. If a coin escrow device does not operate reliably, the vending system may be damaged by an irate user and revenue will be lost to the owner of the system.
Additionally, a coin escrow must be able to hold a large number of coins while resisting jamming and without causing erroneous discharge of the coins. The number of coins in a coin escrow can cause a significant variation in the amount of friction between bearing points of a coin escrow device. Some coin escrow devices, for example are required to hold a minimum of forty coins or more. A coin-operated system which is subject to jamming is likely to incur substantial down-time which results in dissatisfaction of users and requires costly additional maintenance.
A further requirement for many coin escrow devices is low power consumption. In certain applications, such as pay telephones, the drive power for the device is derived from a limited line power supply. Low cost is also an important requirement in most applications for which coin escrows are used.
PCT Application No. WO1997US13421 to Faes et al. discloses a coin escrow apparatus for pay telephones. The apparatus described in the Faes et al. application includes a housing defining a coin hopper, a coin acceptance chute, a coin return chute, and a door mounted within the housing for selective movement between an escrow position, an acceptance position and a return position. The apparatus also includes structures for selectively moving the door between its escrow, acceptance, and return positions. These structures include elements for guiding the door for pivotal movement, a pivotal support member element and an actuator for pivoting the pivotal support member element. The apparatus disclosed in Faes et al. uses friction points between the door and the pivotal support member element. This apparatus tends to suffer from the reliability problems discussed above and is susceptible to jamming. Accordingly, a longstanding need still remains for a coin escrow device which is reliable and resists jamming over a lengthy service life for the telephone.